spring拦截器.学习.

接口类
package com.test.TestSpring3;

public interface UserService // 被拦截的接口
...{
    public void printUser(String user);
}

实现类

package com.test.TestSpring3;

public class UserServiceImp implements UserService // 实现UserService接口
...{
    public void printUser(String user) ...{
        System.out.println("printUser user:" + user);// 显示user
    }
}

 AOP方法拦截器
package com.test.TestSpring3;

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;

public class UserInterceptor implements MethodInterceptor
// AOP方法拦截器
...{

    public Object invoke(MethodInvocation arg0) throws Throwable ...{

        try ...{

            if (arg0.getMethod().getName().equals("printUser"))
            // 拦截方法是否是UserService接口的printUser方法
            ...{
                Object[] args = arg0.getArguments();// 被拦截的参数
                System.out.println("user:" + args[0]);
                arg0.getArguments()[0] = "hello!";// 修改被拦截的参数

            }

            System.out.println(arg0.getMethod().getName() + "---!");
            return arg0.proceed();// 运行UserService接口的printUser方法

        } catch (Exception e) ...{
            throw e;
        }
    }
}

测试类.
package com.test.TestSpring3;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.web.context.support.WebApplicationContextUtils;

public class TestInterceptor ...{

    public static void main(String[] args) ...{
        ApplicationContext ctx = new FileSystemXmlApplicationContext(
                "classpath:applicationContext.xml");
//        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");    
        
        UserService us = (UserService) ctx.getBean("userService");
        us.printUser("shawn");

    }
}

 

配置文件如下:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>

    <bean id="userServiceImp"
        class="com.test.TestSpring3.UserServiceImp" />

    <bean id="userInterceptor" class="com.test.TestSpring3.UserInterceptor" />

    <bean id="userService"
        class="org.springframework.aop.framework.ProxyFactoryBean">
        <property name="proxyInterfaces">
            <value>com.test.TestSpring3.UserService</value>
        </property>
        <property name="target">
            <ref local="userServiceImp" />
        </property>
        <property name="interceptorNames">
            <list>
                <value>userInterceptor</value>
            </list>
        </property>
    </bean>

</beans>

 

输出:

 user:shawn
printUser---!
printUser user:hello!      调用方法的时候 传入的值被拦截修改了.